I’ve pretty much given up on reading the rest of the Nierenberg report (1983). It’s long on words, and I’m short on time. After about 2/3 of the way through the synthesis, it gets pretty wishy-washy. I skimmed chapter 2, which was written by an economist, and it too seems wishy-washy. Although with the predictions of CO2 rise that they give for a “stringent tax” on CO2 starting in 2000 still resulting in CO2 concentration of 660 ppm in 2100, which is still in the “we’re all f—ed” range.

The “stringent tax” is described two ways in the text. In the caption to table 2.18, it is described as a “gradually increasing tax rising linearly from zero to $8 per ton [coal equivalent] between 2000 and 2020, from $8 to $68 per ton between 2020 and 2040, from $68 to $90 per ton between 2040 and 2060, and remaining at $90 per ton thereafter.” In the text, it describes the tax as “plac[ing] 60% surcharges on the prices of fossil fuels”. The “stringent tax” results in a reduced atmospheric CO2 concentration of about 120 ppm from the business as usual scenario over about 120 years.

I’d like to note that as of as little as a month ago, these same sort of “experts” who were advising to buy AIG, right when it was in its final death spiral.

$85 Billion. Or 255 days of Iraq War equivalent. Too big to fail my arse. CEO gets $7 million for 3 months “work” running it into the ground. How does one get that job? I’m sure massive incompetence is involved - which may make me qualified, according to some recent commenters here.

But back to Chicken Little. On page 48, Oreskes says:

Even without that, thermal expansion alone would produce 70 cm of rise — a not insignificant figure.

This comes right after a previous sentence that ends with “Revelle concluded.” One might be tempted to think that Revelle concluded that thermal expansion alone would lead to 70 cm of sea level rise during an unspecified time period. And I suppose it would, given a long enough period of warming.

Does the juxtaposition of the last sentence make it sound like Revelle actually concluded it? View image from the PDF; click to enlarge.

What did Revelle actually say about thermal expansion?

We thus arrive at a rise in sea level about 100 years from now of at least 30 cm, resulting from ocean warming [thermal expansion] A similar calculation has been made by Gornit et al. (1982); they estimate a rise of 20-30 cm during the next 70 years.

The next paragraph explains where the 70 cm comes from. It is obviously not due to thermal expansion alone.

Adding this estimate for ocean warming to our estimates for melting in Greenland and Antarctica and in alpine glaciers, we arrive at a probable rise in sea level during the next 100 years of about 70 cm.

Flipping back a few pages, we can find where the 70 cm number comes from. They estimate (Ambach (1980); Manabe and Wetherald (1975)] that a warming of 3C would result in a melting of the Greenland ice sheet equivalent to 12 cm in 100 years. Revelle then says “We are unable to calculate the rise in sea level due to a possible retreat in alpine glaciers.” He then estimates that their melting would result in a rise of 12 cm in sea level over the next 100 years (unsourced).

But that only gives a 24 cm rise over 100 years in addition to the 30 cm from thermal expansion. A total of 54 cm, compared to the final value given of 70 cm. The difference lies in the next paragraph.

Adding these figures for accelerated ice loss from Greenland and alpine glaciers to the estimated rate of loss from ice melting over the past 50 years of 17 cm per century, we arrive at a probable rise in sea level resulting from an increase in the mass of ocean water during the next century of 41 cm.

The estimates of loss during the next century were added to estimates of loss during the previous half-century, and the results were presented as the estimates of loss during the next century. Presumably because it was expected that sea levels would be accelerating, although the text is not clear.

[Initial average surface ocean temperatures (Sverdrup et al. (1942, P.127))] were added to the change in average surface temperature for each latitude band projected by Flohn (1982) for the middle of the twenty-first century, assuming a doubling of atmospheric carbon dioxide and the probable increase in other greenhouse gases during the next 70-80 years.*

The * refers to the footnote:

*Flohn’s projected global temperature rise is 4.2C, somewhat higher than the value of 3C used in the earlier discussion.

He used a climate sensitivity of 4.2C for doubled CO2 to calculate the sea level rise due to thermal expansion. Since the actual sensitivity is much lower, this will bias the results toward higher values. A naive approach to correct this for the real CO2 sensitivity would be to assume that the change in sea level scales linearly with change in temperature. Using this naive assumption, the value of the sensitivity is 40% high, thus the rise in sea level due to thermal expansion would be 40% high. The naive value for a sensitivity of 3C for doubled CO2 is 18 cm per century.

I’ve converted the rise due to thermal expansion to a value consistent with a sensitivity of 3C because the other values [Greenland melting, alpine glacier melting] were derived using a sensitivity of 3C. It doesn’t make sense to me why you would want to compare values of sea level rise due to different processes when different sensitivities were used to derive them. It seems like comparing apples to oranges.

So ignoring the acceleration of ice loss from Greenland, including the rise due to glacial melting, and correcting the thermal expansion term for a realistic climate sensitivity, I arrive at a value of sea level rise of 42 cm in the next century (12 cm + 12 cm + 18 cm, from 1983). Compared to recent studies [28 to 34 cm rise from 1990 to 2100, Church and White, 2006], this value is still too high.

Finally, I’m going to comment on the second part of Oreskes’ sentence, “a not insignificant figure” - referring to the 70 cm rise projected by Revelle in the coming century. This is unreferenced, and I could not find it in Revelle’s chapter. One has to go back to the synthesis to find a comment like that.

As explained by Revelle, melting of land ice and thermal expansion of the ocean may lead to a rise of about 70 cm in global sea level over the next 100 years, continuing thereafter. Many shoreline problems (for example, coastal erosion, storm surges, and salinity of groundwater) are sensitive to sea-level changes on the order of decimeters, and 70 cm, though modest-sounding on a calm day at the seashore, could effect a variety of unwelcome changes.

Thus, it’s not Revelle’s chapter on sea level rise that warns of the potential consequences of a small rise in sea level. It comes from the synthesis, which Oreskes argues was written, and hijacked, by Nierenberg.

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